Polymyositis has been associated with several viral infections, and a spectrum of immune-related diseases may occur with hepatitis C virus (HCV) infection. Both polymyositis and HCV infection may be accompanied by interstitial lung disease; however, no association between polymyositis and HCV infection has been reported previously. We report a new association in a patient with HCV infection: anti-Jo-1 positive polymyositis and interstitial lung disease.